135218-48-3Relevant academic research and scientific papers
Ruthenium Catalysts Supported by Amino-Substituted N-Heterocyclic Carbene Ligands for Olefin Metathesis of Challenging Substrates
César, Vincent,Zhang, Yin,Ko?nik, Wioletta,Zieliński, Adam,Rajkiewicz, Adam A.,Ruamps, Mirko,Bastin, Stéphanie,Lugan, No?l,Lavigne, Guy,Grela, Karol
, p. 1950 - 1955 (2017/02/15)
N-Heterocyclic carbene (NHC) ligands IMes (Formula presented.) and IMes (Formula presented.) derived from the well-known IMes ligand by substituting the carbenic heterocycle with one and two dimethylamino groups, respectively, were employed for the synthesis of second-generation Grubbs- and Grubbs–Hoveyda-type ruthenium metathesis precatalysts. Whereas the stability of the complexes was found to depend on the degree of dimethylamino-substitution and on the type of complex, the backbone-substitution was shown to have a positive impact on their catalytic activity in ring-closing metathesis, with a more pronounced effect in the second-generation Grubbs-type series. The new complexes were successfully implemented in a number of challenging olefin metathesis reactions leading to the formation of tetra-substituted C=C double bonds and/or functionalized compounds.
Ruthenium-catalyzed olefin metathesis double-bond isomerization sequence
Schmidt, Bernd
, p. 7672 - 7687 (2007/10/03)
A novel ruthenium-catalyzed tandem ring-closing metathesis (RCM) double-bond isomerization reaction is described in this paper. The utility of this method for the efficient syntheses of five-, six-, and seven-membered cyclic enol ethers is demonstrated. It relies on the conversion of a metathesis-active ruthenium carbene species to an isomerization-active ruthenium-hydride species in situ. This conversion is achieved by using various additives. Scope and limitations of the different protocols are discussed, and some mechanistic considerations based on 31P and 1H NMR spectroscopic studies are presented.
